In the field of image processing, conventionally, there has been developed a technique for detecting a person from an image. The technique for detecting a person from an image is applied to various apparatuses including security cameras for detection abnormalities such as intrusion of a person, watching cameras for detection of a person falling down at care facilities or the like, form analyzer with sports video, other image processing apparatuses. However, most of these image processing apparatuses are produced on the precondition that images from cameras installed on the ceiling or the pillars are analyzed. That is, these image processing apparatuses detect a person on the assumption that the person is seen in a predetermined orientation so as not to increase a processing time.
For example, Non Patent Literature 1 discloses a technique for detecting a standing person from an input image obtained by shooting the person in a predetermined orientation. In addition, Non Patent Literature 2 discloses a technique for detecting a lying person from an input image obtained by shooting the person in a predetermined orientation.